1. Field of the Invention
The present invention relates to a microwave oven, in particular to an automatic cooking compensation apparatus of a microwave oven and a method thereof, which is capable of solving a port number restriction of a micro computer when data compensation is performed in accordance with automatic cooking time.
2. Description of the Prior Art
An automatic cooking using a microwave oven is executed according to an predetermined algorithm. Herein, the automatic algorithm yields a proper value based on an experimental value in product developing stage and performs the cooking by adapting it. However, compared with the situation in pilot-production of microwave oven, distributing range in electromagnetic wave varies with outer factor in the microwave oven after mass-production. Herein, the cavity placed beside a controller of the microwave oven is space for depositing and heating foodstuff. Accordingly, there is a need to perform data compensation about automatic cooking time of an automatic cooking menu after the microwave oven is produced. Herein, menus which require the data compensation are popcorn, beverage etc., and menus which do not requires the data compensation are potato, vegetable, snack etc.
As depicted in FIG. 1, the conventional microwave oven comprises a key scan and an input circuit 20 for inputting a key signal according to a key selection of a user by scanning the key with a certain time interval, and an automatic cooking data alternation detecting circuit 10 for detecting data alternation according to the automatic cooking menu as separated input ports.
The automatic cooking data alternation detecting circuit 10 uses an additional input port of a microcomputer, one automatic cooking time data alternation port is allotted to every input port by weight or dish category.
In other words, as depicted in FIG. 2, a line for providing data alternation information according to the automatic cooking time is connected to input ports P1, P2 of the microcomputer in the conventional microwave oven. Accordingly, codes 25, 35 allot data alternation information by differentiating a voltage value inputted to the microcomputer by each different resistance.
FIG. 3 is a flow chart illustrating the cooking time compensation operation of the microwave oven automatic cooking menu. As an example, a cooking time data alternation process about popcorn cooking will now be described.
A user selects a dish menu through the key scan and input circuit S100, and inputs a cooking start key S1110. The microcomputer judges whether the user select menu is the menu requiring data alternation for cooking time compensation S120. When the menu is not the menu requiring the cooking time compensation, the microcomputer perform the cooking by controlling an oscillation circuit during the cooking time T1 set in advance S160, 170.
When the user select menu is the popcorn dish requiring the data alternation for the cooking time compensation S100, the microcomputer reads an analog/digital value according to the data alternation of the cooking time from the automatic cooking data alternation detecting circuit S130.
In other words, the microcomputer reads the data from the input port P1 or P2 set in advance in accordance with weight of the popcorn through the S130, and yields add-subtract time T2 for the cooking time compensation according to the value S140.
And, the final cooking time is yielded by adding the add-subtract time T2 of the S140 to the automatic cooking time T1 set in advance and the automatic cooking according to it is controlled S150, 170.
Meanwhile, in the popcorn cooking, data alternation about the cooking time is not performed uniformly by weights, but the data add-subtract rate of the cooking time is different in accordance with 1.75 ounce, 3.0 ounce, 3.5 ounce. Accordingly, the microcomputer has to allot the one input port by the weight of the popcorn. When there is the three popcorn weights as described above, the microcomputer needs the three input ports.
However, when a low priced microcomputer is used, the number of the input ports for allotting to the automatic cooking data alternation detecting circuit are limited as two usually. Accordingly, when the input port P2 is allotted to the 1.75 ounce data requiring the most strict cooking time data so as to be variable, it is difficult to perform the accurate cooking about the 3.5 ounce popcorn cooking.
In addition, when the microcomputer having the high capability is used in order to increase the number of the input port, the manufacture cost increases. In other words, the conventional automatic cooking compensation apparatus of the microwave oven has a limit for performing the cooking time compensation with the conventional method which allots the ports of the microcomputer by the weight and dish menu when the cooking time has to be compensated in accordance with the automatic cooking menu and the cooking time compensation has to be adjusted differently by the weight or dish menu.
Accordingly, the object of the present invention is to provide an automatic cooking compensation apparatus of a microwave oven and a method thereof which is capable of performing cooking time data compensation without being restricted by number of ports when the cooking time data compensation is required in an automatic cooking menu of a microwave oven.
In order to achieve the above-mentioned object, the automatic cooking compensation method of the microwave oven according to the present invention comprises a designating step for designating a key input port as an analog port just after power is applied, a reading and storing step for reading and storing a data value for the automatic cooking compensation to the analog port, a alternation step for changing the key input port into the general key signal input port, a judging step for judging whether a select dish menu is the menu requiring the data compensation, and a compensating step for compensating the cooking time of the select dish menu on the basis of the stored compensation data value.
The automatic cooking compensation apparatus according to the present invention comprises a key matrix for scanning a key and outputting a signal corresponding to the selected key, an automatic cooking data alternation detecting means using an output port of the key matrix in conjunction with the key matrix in order to output a plurality of analog signals by dividing data alternation output signals differently each other through the key matrix output port, and a microcomputer connected with the output port of the key matrix with its input port in order to read an output signal of the automatic cooking data detecting means by designating the input port as an analog port when initial power is provided, and read a key selected in the key matrix by altering the input port to a general key input port when a main menu operates.